This happened to me too… I reconnected the cables and it worked after that.

Amazing guide! Thank you very much… It worked! The ifixit kit was fantastic! The bulk of the time was spent extracting small pieces of glass from around the edges as it was a bad break - ~2hrs worth. The i-opener helped, but worked quite slowly. The small metal lever that came with the replacement screen was extremely useful too. Just to note, the first time I replaced the screen, I could swipe in one position, but not use the keypad. I took the screen off, re-connected the cables and ensured the white lines were no longer visible on the connection. When I replaced the top layer again, it worked perfectly.